Lots of storage in these baby's at the back and underneath the seats, the fuel tank only uses a small amount of the space available and can be moved forward or back probably 18 inches if you really want to maximize the space. Here are some pictures of my EV Conversion where I am storing the batteries at the back and where the fuel tank used to be, I still have 24 inches of storage under the seats. I am just building the new floor with hatch covers, I will add these pics when I am done.

Rear Battery storage 24 X 30

rear storage.jpg (33.68 KiB) Viewed 12794 times

Here is a shot of the underside, I found a perfect stainless steel bucket about 20/30 with a rolled lip that is supported by the frame and a couple of 1/2 inch thick aluminum spaces to the side frame.

Stainless bucket underside

rear storage underside.jpg (25.3 KiB) Viewed 12794 times

Here is a shot of the 4X4 project where I have removed the entire front seat area to use the space to run the tranny to the rear axle. I am placing the seats on rotating pedestals and using that space for more floor space in the cab instead. I will probably have a pop up table behind the seats.

underseat storgage.jpg (29.51 KiB) Viewed 12794 times

Finally back to the EV here is the forward battery storage I created by removing the fuel tank.

Middle battery storage

sfront storgae.jpg (33.08 KiB) Viewed 12794 times

I am actually thinking about using this space on the 4X4 project and putting duel saddle tanks on the rear underside or in the pockets behind the seats left and right.